Biased tilt mechanisms, especially useful in swivel chairs and the like



Nov. 30, 1965 w. P. BAERMANN 3,220,687

BIASED TILT MECHANISMS, ESPECIALLY USEFUL IN SWIVEL CHAIRS AND THE LIKE Filed July 28, 1964 2 Sheets-Sheet 1 INVENTOR. 7 5? PBAERMA/V/V WAL BY I s T \Q q Q q q w 1 Nov. 30, 1965 w. P. BAERMANN 3,220,687

BIASED TILT MECHANISMS, ESPECIALLY USEFUL IN SWIVEL CHAIRS AND THE LIKE Filed July 28, 1964 2. Sheets-Sheet 2 INVENTOR.

3/ WALTER PBAERMA/VN BY I) United States Patent 3,220,687 BIASED TILT MECHANISMS, ESPECIALLY USEFUL IN SWIVEL CHAIRS AND THE LIKE Walter P. Baermaun, 600 Asheville Road, Waynesville, N.C. Filed July 28, 1964, Ser. No. 385,738 Claims. (Cl. 248-378) This application is a continuation-in-part of my copending applications Serial No. 303,643, filed Aug. 21, 1963, and Serial No. 350,460, filed Mar. 9, 1964.

This invention, in general, pertains to resiliently-biased tilt mechanisms, and, more particularly, pertains to resiliently biased tilt mechanisms embodying a swivel function and particularly adapted for use in tilt-swivel articles of furniture such as tilt-swivel chairs and the like.

There are many known types of tilt-swivel mechanisms for tilt-swivel chairs. Most of these mechanisms are relatively bulky, and the component parts are arranged so as to be relatively unattractive. Furthermore, the mechanism for adjusting the tension of the resilient bias, e.g., a spring bias, is so bulky as to constitute a serious problem to the furniture designer in creating an aesthetically-pleasing chair or the like.

This invention pertains to improvements in tilt mechanisms wherein the resilient bias for the tilt mechanism is housed in the center post which supports the chair. The invention further pertains to improvements in mechanism for quickly and conveniently altering the bias of the resilient bias mechanism, such as a coil spring, a rubber sleeve, or the like, to adjust the degree of resistance to tilting to the users desires. One aspect of the invention pertains to tilt-swivel mechanisms embodying a mechanism for raising or lowering the height of the chair seat or other structure supported by the tilt-swivel mechanism wherein the height adjustment is accomplished by a threaded post which remains hidden from view in a sleeve appropriately provided on the tilt-swivel mechanism. Furthermore, in the latter case, the invention also provides a combination wherein the sleeve is turned to provide the height adjustment as well as means for quickly detaching the sleeve, height adjustment mechanism, and resilient bias mechanism from the base of the chair for the purpose of disassembly of these mechanisms from the chair base for repair or other purposes. Still another aspect of the invention relates to tilt-swivel mechanisms which are essentially entirely housed in a vertical post constituting part of the support post for the chair seat or other structure supported by the tilt-swivel mechanism.

Briefly, the tilt and/or tilt-swivel mechanisms of the invention comprise a frame, mounting bracket, plate, or other structure tiltably supported on a head member of the mechanism. The head member is threadedly mounted on a mounting tube, which is a component of the support post. A resilient-bias mechanism embodying a bias member such as a coil spring, elastomer body or the like is mounted in the tube. The upper end of the bias member is operatively associated with the tiltable frame, bracket, etc., so that the bias member resiliently resists tilting of the tiltable member. The amount or degree of resilient bias of the bias mechanism acting against such tilting action is adjusted by threading the head member onto or off of the mounting tube. In the case of a coil spring as the resilient bias member, the spring is compressed in the tilting action. In the case of an elastomer body, the latter may be either compressible or essentially incompressible, but laterally deformable, as Will be explained hereinafter in more detail.

In mechanisms of the invention utilizing a height adjustment for changing the height of the seat or other structure supported by the tilt-swivel mechanism, this adjustment is achieved by providing a height adjustment sleeve or tube in surrounding relationship to the mounting tube. This height adjustment sleeve or tube turns a ring nut threadedly and operatively connected to a threaded height adjustment post or shaft which fixedly supports the mounting tube and the structure housed therein whereby the mounting tube and its associated structure, including the head member and tiltable member thereon, are raised or lowered when the threaded shaft or post is raised or lowered via rotation of the ring nut though the rotation of the height adjustment sleeve or tube. This structure eliminates the need for bulky, knobbed handles and the like which are commonly used for adjusting the degree of bias of the resilient bias for the tilt mechanism of the chair.

The invention, its purposes and objectives, and advantages accruing therefrom will be more fully appreciated from the following description of several preferred embodiments of the generic invention herein disclosed. These preferred embodiments are illustrated in the accompanying drawings, wherein:

FIG. 1 is a section taken on section plane 1-1 of FIG. 2 through a tilt-swivel support structure embodying a coil spring resilient bias and a height adjustment mechanism;

FIG. 2 is a section view of said support structure taken on section plane 22 of FIG. 1;

FIG. 3 is a section view taken on section plane 3-3 of FIG. 1;

FIG. 4 is a section view taken on section plane 4-4 of FIG. 1; and

FIG. 5 is a fragmentary, diametric section, in fragment, of a mechanism similar to that of FIG. 1 but embodying an elastorner bias member.

Referring to the drawings, there is shown in FIG. 1 a chair seat part 10 which is a channel plate comprising a mounting bracket, part of a seat frame, or the like tiltably and pivotally supported on a tilt-swivel mechanism embodying a seat-height adjustment mechanism. These mechanisms comprise a hollow cylindrical head member 11 having a loop-like bar or yoke 12 made integrally with or fixedly attached by welding or the like to a side of the head member 11. The bar or yoke 12 is structurally strong because its upper edge 13 constitutes both a stop and a rest member for the seat part 10, precluding pivotal movement in a clockwise direction as viewed in FIG. 1 beyond the position shown in that figure. The bar or yoke 12 comprises a rear cross-bar 14 secured or integrally formed at its mid-section with the head member 11, side bars 15 and 16, a curved front bar 17, and a reinforcing, crossplate 18.

The sides 19 and 20 of the channel seat part 10 fit over the side bars 15 and 16. The sides 19 and 20 have mounted therein the ends of a pivot shaft or pin 21 extending across the channel seat part 10 and pivotally supported in side bars 15 and 16, whereby the seat part It is pivotally supported on the head member 11.

A semi-cylindrical bar 22 may be included in the seat part 10 on the opposite side of the head member 11, the ends of which bar are attached to the sides 19 and 21) to enclose more completely the mechanism adjacent thereto and to reinforce the seat part 10.

The top 23 of the channel seat part 10 has formed therein a cylindrically curved section 24, in the concave, downwardly-facing face of which is seat a roller 25. The opposite side of the roller 25 is seated in the upwardly facing, concave face of a cylindrically curved section 26 of a disc 27.

The disc 27 is a pressure plate against which bears the upper end of coil spring 28, the lower end of which is sup ported on the ring collar 29 fixedy secured to the lower end of mounting tube 30. The latter houses the coil spring 28 and also supports, by the interengaged threads 3 33, at its upper end the head member 11. These threads play an important function in adjusting the amount or degree of resilient bias of the spring 28 in its resistance to the tilting action heretofore described. This aspect of the invention will be described in greater detail hereinafter.

Thus, the coil spring compresses when seat part is pivoted in the counterclockwise direction, as viewed in FIG. 1, through pressure applied via roller to the disc 27. The roller can slide relative to the concave seats in sections 24 and/or 26 to compensate for the changing, relative angularity between seat part 10 and disc 27 as the part 10 pivots, the disc 27 remaining substantially horizontally under the bias of spring 28. The degree of tilt of part 10 is limited to the point at which it and the head member 11 or other stop means come into contact. As aforestated, the normal, rest position is that shown in FIG. 1 wherein the channel part 23 abuts against the edge 13 of the loop-like bar 12. The roller 25 may be made of metal, or more preferably, of a strong synthetic polymer resin, preferably one impregnated with a solid lubricant such as molybdenum disulfide or a liquid or semisolid lubricant. Also, a ball (not shown) may be used in lieu of roller 25.

The lower end of the mounting tube 30 is fixedly mounted on a collar 19 provided at the lower end of the mounting tube 30. The collar 29, in turn, is fixedly supported on the upper end of a threaded, height adjustment shaft or post 31, which extends into the hollow, tubular base 32 of the chair or other structure. The threaded shaft or post 31 is journalled slidably for up and down movement and supported in the spaced, ring bushings 34' and 34 fixedly supported in base 32 but is not threadedly connected therewith. The rod or shaft 31 has an elonated, vertical slot 35 in the'side thereof.

The threads of the shaft or post 31 are threadedly connected with a height adjustment nut 36. The height adjustment nut 36 in turn is fixedly mounted in a tubular, hollow sleeve 37 which can be rotated relative to the mounting tube 30. By turning the height adjustment sleeve 37, the height adjustment nut 36 can be turned to thread the rod or post 31 up or down, as the case may be. The structure as illustrated in FIG. 1 shows the mechanism in the lowermost position. When the sleeve 37 and nut 36 are turned in the appropriate direction, the post 31 rises, raising with it the mounting tube 30 and all of the structure supported thereby. The upper end of the mounting tube 30 moves out of the upper end of the height adjustment sleeve 37. As the threaded rod or post 31 and structure supported thereon moves upwardly, the threaded post 31 remains hidden from view inasmuch as it is screened or hidden by the height adjustment sleeve 37.

The height adjustment nut 36 is rotatably supported on a bearing washer 38 made of an anti-friction material. When the seat or other structure 10 is swiveled, the unit comprising the threaded shaft 31, collar 29, mounting tube 30, structure housed therein, head member 11, and seat part 10 swivel together as a unit, along with the height adjustment sleeve 37. This entire unit is swivelly supported on the bearing washer 38. In order to keep the nut 36 and the height adjustment sleeve 37 rotating with the unit during normal swivel movement of the chair seat or the like, the upper surface of the bearing washer 38 is provided with at least one radially extending, rib-like boss 39 which is adapted to matingly seat in radial groove 39 in the undersurface of the nut 36. Furthermore, the hearing washer 38 has an ear 40 which extends into the vertical slot 35 in the threaded rod 31. Thus, with the usual weight on the chair seat or the like in the normal swiveling movement of the chair, the boss 39 remains seated in the groove so that the nut rotates as a unit with the bearing washer 38. The relative motion providing the swiveling function occurs at the faces of the bearing washer 38 and the upper surface of the collar 34, which is fixedly secured in the base 32 of the chair structure or the like. When, however, the height adjustment sleeve 37 is turned to change the relative height of the seat of the chair, the boss 39 may become unseated from the groove so that the nut 36 can turn relative to the rod 31, as well as the bearing washer 38, and perform the height adjustment function.

In order to vary the resilient bias of spring 28 against the aforedescribed tilting action of the chair seat, the nut 36 has a stepped, radial opening 41 in which is slidably mounted the flange 42 and pin or stud 43 of a coilspring biased, push button 44, the head of which projects through an opening in the sleeve 37. Flange 42 stops push button 44 from being ejected through the opening in sleeve 37. The aforesaid bias adjustment is accomplished by depressing the push-button 44 while tightly gripping the height adjustment sleeve 37 and rotating the chair seat or other structure supported on the mechanism, to which the seat part 10 is attached. Within one revolution, the pin or stud 43 of the push-button 44 falls into the slot 35 of the shaft 31, thus locking together the height adjustment sleeve 37 and the rod or shaft 31, as well as the mounting tube 30 fixedly attached to said shaft or rod. This prevent rotation of the mounting tube 30 by virtue of the tight grip of the hand on the height adjustment sleeve 37. Continued swivel or rotational movement of the chair or other structure supported on the seat part 10 causes the head member 11 to be rotated onto or off of, as the case may be, the threaded, upper end of the mounting tube 30. If the head member is threaded off the upper end of mounting tube 30, the spring 28 is decompressed, thereby decreasing the bias of the spring against tilting of the seat. Conversely, the spring is compressed further, and its bias is increased, by threading the hollow head member 11 further into the post 30.

The entire tilt-Swivel-height adjustment mechanism heretofore described is detachably held on the tubular base portion 32 by a quick detach mechanism. The latter structure comprises a generally U-shaped, spring lock clip 45 having a head portion 46 extending through a slot in the lower end of the height adjustment sleeve 37. The spring lock clip 45 is seated in an annular groove 47 around the outer wall of the upper bushing 34, which is fixedly held in the tubular base portion 32. The lips 48 at the ends of the springable arms of the spring lock clip 45 matingly seat against the cylindrical side wall of the groove 47. With the head 46 projecting through the slot in the tubular, height adjustment sleeve 37 as shown in FIGS. 1 and 4, the tilt-swivel-height adjustment mechanism is held on the base portion 32. When the head portion 46 is pushed inwardly to unseat it from the groove in the sleeve 37, the arms of the spring lock clip 45 spread apart and allow the head portion 46 to be pushed inside the sleeve 37. This allows the tilt-swivel-height adjustment mechanism, including the threaded rod or post 31, to be lifted out of the tubular base portion 32. In the locking orientation as shown in FIGS. 1 and 4, the lips 48 slide on the wall of the groove 47 when the sleeve 37 rotates relative to the base 32 either during normal swiveling action or during the height adjustment function.

The embodiment of FIG. 5 is similar to that of FIGS. 1-4, above described. The primary difference lies in the use of a substantially cylindrical, elastomer bias member 50 having an outside diameter smaller than the inside diameter of mounting tube 30 and hollow head member 11. This leave an annular clearance space 51 into which the elastomer bias member can expand latenally when its ends are compressed between disc 27 and collar ring 29 during tilting and/or bias adjustment. The clearance is important in the case of elastomer members made of substantially incompressible elastomers which deform elastically but do not compress. If the elastomer member 50 is made of a compressible material such as a foamed or cellular elastomer, the clearance 51 is not necessary. Also, in this case, it may be advantageous to make the roller 25 a ball to allow more free action when rotating head member 11 relative to mounting tube 30 during bias adjustment.

The chair mechanisms aforedescribed can be used on many types of chairs, e.g., oflice chairs, living room chairs, other chairs designed chiefly for use in home funnishings, chairs in carriers such as trains, airplanes, etc., and the like. The tilt-mechanisms, with or without the swivel mechanisms, can be employed in chairs designed for rocking.

It is thought that the invention and its numerous attendant :advantages will be fully understood from the foregoing description, and it is obvious that numerous changes may be made in the form, construction and arrangement of the several parts without departing from the spirit or scope of the invention, or sacrificing any of its attendant advantages, the forms herein disclosed being preferred embodiments for the purpose of illustrating the invention.

The invention is hereby claimed as follows:

1. A resiliently biased tilt mechanism comprising a hollow, vertical mounting post, a hollow head mounted by threads on the upper end of said post, said head being movable up and down relative to said post by rotatably threading said head relative to said post, a tiltable member, pivot means supporting said tiltable member on said head for pivotal movement of said member about a horizontal pivot axis laterally offset relative to said post, a resilient, longitudinally compressible bias member in said post, means supporting the lower portion of said bias member in said post, the upper portion of said bias member being in said hollow head, a pressure plate having an upwardly facing, concave face, said pressure plate being seated on the upper end of said bias member, means providing a downwardly facing, concave face on said tiltable member opposite said first-mentioned concave face, and a round surfaced member having its rounded surface in the respective concave faces, through which rounded member pressure is transmitted between said tiltable member and said bias member, whereby tilting of said tiltable member about said axis is resisted by said bias member and the [amount of bias transmitted between said bias member to said tiltable member via said pressure plate and said round surfaced member is adjustable in response to rotatable threading of said head relative to said post to longitudinally elongate or compress said bias member.

2. A tilt mechanism as claimed in claim 1, a base member, means supporting said mounting post for swivel movement relative to said base member, and means for locking said base member and said mounting post against relative swivel movement when threading said head on said mounting post.

3. A tilt mechanism as claimed in claim 1 wherein said bias member is a coil spring.

4. A tilt mechanism as claimed in claim 1 wherein said tiltable member is a frame adapted to support a chair seat, said frame including a plate extending above and across said hollow head, and a curved section in said plate directly above said hollow head and forming said downwardly facing, concave face.

5. A tilt mechanism as claimed in claim 1 wherein said tiltable member is a frame adapted to support a chair seat, said frame including a channel member with downwardly directed sides, and said pivot means comprising a yoke rigidly mounted on and extending laterally from said hollow head, said yoke being positioned between said sides of said channel, and horizontal shaft means pivotally supporting said channel sides on said yoke.

References Cited by the Examiner UNITED STATES PATENTS 607,283 7/ 1898 Schaffner 248375 X 805,522 11/ 1905 Bethke 248-402 1,344,092 6/1920 Shaw 2484l5 X 1,589,847 6/1926 Hansen 248415 X 2,106,174 1/1938 Herold 248375 FOREIGN PATENTS 85,993 8/ 1955 Norway.

CLAUDE A. LE ROY, Primary Examiner. 

1. A RESILIENTLY BIASED TILT MECHANISM COMPRISING A HOLLOW, VERTICAL MOUNTING POST, A HOLLOW HEAD MOUNTED BY THREADS ON THE UPPER END OF SAID POST, SAID HEAD BEING MOVABLE UP AND DOWN RELATIVE TO SAID POST BY ROTATABLY THREADING SAID HEAD RELATIVE TO SAID POST, A TILTABLE MEMBER, PIVOT MEANS SUPPORTING SAID TILTABLE MEMBER ON SAID HEAD FOR PIVOTAL MOVEMENT OF SAID MEMBER ABOUT A HORIZONTAL PIVOT AXIS LATERALLY OFFSET RELATIVE TO SAID POST, A RESILIENT, LONGITUDINALLY COMPRESSIBLE BIAS MEMBER IN SAID POST, MEANS SUPPORTING THE LOWER PORTION OF SAID BIAS MEMBER IN SAID POST, THE UPPER PORTION OF SAID BIAS MEMBER BEING IN SAID HOLLOW HEAD, A PRESSURE PLATEK HAVING AN UPWARDLY FACING, CONCAVE FACE, SAID PRESSURE PLATE BEING SEATED ON THE UPPER END OF SAID BIAS MEMBER, MEANS PROVIDING A DOWNWARDLY FACING, CONCAVE FACE ON SAID TILTABLE MEMBER OPPOSITE SAID FIRST-MENTIONED CONCAVE FACE, AND A ROUND SURFACES MEMBER HAVING ITS ROUNDED SURFACE IN THE RESPECTIVE CONCAVE FACES, THROUGH WHICH ROUNDED MEMBER PRESSURE IS TRANSMITTED BETWEEN SAID TILTABLE MEMBER AND SAID BIAS MEMBER, WHEREBY TILTING OF SAID TILTABLE MEMBER ABOUT SAID AXIS IS RESISTED BY SAID BIAS MEMBER AND THE AMOUNT OF BIAS TRANSMITTED BETWEEN SAID BIAS MEMBER TO SAID TILTABLE MEMBER VIA SAID PRESSURE PLATE AND SAID ROUND SURFACES MEMBER IS ADJUSTABLE IN RESPONSE TO ROTATABLE THREADING OF SAID HEAD RELATIVE TO SAID POST TO LONGITUDINALLY ELONGATED OR COMPRESS SAID BIAS MEMBER. 